do tyres with sparse knobs like this ever have *worse* grip than tyres with more concentrated knobs, if so in what terrain/conditions, and is it significantly worse?

is the difference between single ply and dual simply a cost/durability trade off or is there more to it?

why does this tyre advise ‘race only – not for your local trail’ – is it for the tyre’s benefit (durability), the trail’s (erosion), or the rider’s (danger from less grip), or a mix?

cheers

Wet Screams will certainly tear up a soft trail if you’re not careful, the knobs are quite tall.

If the trail is hard and smooth, the sparse knobbed tyres can squirm a bit more, which can feel like worse grip

I have used a wet scream – on the back of the tandem – sticks like snot to a blanket but tears teh trails apart. I doubt I will use it again TBH because of that
Teh sparse knobs allow the mud to clear more easily

do tyres with sparse knobs like this ever have *worse* grip than tyres with more concentrated knobs, if so in what terrain/conditions, and is it significantly worse?

open tread is better for mud/dust, closed tread is better for hard pack.

is the difference between single ply and dual simply a cost/durability trade off or is there more to it?

dp will be more durable less prone to side wall cuts/pinch flat, obviously heavier than sp

why does this tyre advise ‘race only – not for your local trail’ – is it for the tyre’s benefit (durability), the trail’s (erosion), or the rider’s (danger from less grip), or a mix?

soft compound wares out quickly.